Shutting down multiple computers on a workgroup

[msasfiaict]

HI,
I am an ICT teacher in a school. I want to shut down student's computers all at the same time and also if they are accessing the internet without permission.
- All PCs have XP.
- ALl are on same workgroup
- All can share files easily
- I tried using shutdown -i and giving commad on cmd but "Access denied"
- THen I checked "Allow remote access" on students PC.
- Again "access denied" using shutdown -i or cmd
- If I use MMC, I am getting RPC server unavailable.

Thanks

 

[silentplanner]

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